The (optional) initial condition is the initial (time = 0) value of the capacitor voltage (in Volts). Note that the initial conditions (if any) apply only if the

You may specify the

- A simple value. This is the capacitance in Farads.

- An expression, as described in the behavioral modeling chapter. The
expression can specify the charge as a function of voltage, or the
capacitance as a function of time.

- A
*model*, as described in the behavioral modeling chapter. The`table`model describes a table of charge vs. voltage.

- A
*model*, which calculates the capacitance as a function of length and width, referencing a`.model`statement of type`C`. This is compatible with the Spice-3 “semiconductor capacitor”.

`CJ`=*x*- Junction bottom capacitance. (Farads / meter
squared). (Default = 0.)

`CJSW`=*x*- Junction sidewall capacitance. (Farads /
meter). (Default = 0.)

`DEFW`=*x*- Default width. (meters). (Default = 1e-6)

`NARROW`=*x*- Narrowing due to side etching. (meters).
(Default = 0.)

`TC1`=*x*- First order temperature coefficient.
(Farads / degree C). (Default = 0.) (Not in Spice.)

`TC2`=*x*- Second order temperature coefficient.
(Farads / degree C squared). (Default = 0.) (Not in Spice.)

`TNOM`=*x*- Parameter measurement temperature. (degrees C.). (Default = 27.) (Not in Spice.)

capacitance = CJ * (L - NARROW) * (W - NARROW) + 2 * CJSW * (L + L - 2 * NARROW)After the nominal value is calculated, it is adjusted for temperature by the formula:

value *= (1 + TC1 * (T-T0) + TC2 * (T-T0)^2)

`DT`-
Time step. The internal time step used for this device for numerical
integration. It is not necessarily the same as the global time step.

`TIME`-
Time. The time of the most recent calculation of this device. It is
not necessarily the same as the global time.

`TIMEOLD`-
The time of the previous calculation of this device. It is not
necessarily the same as the global time.

`TIMEFUTURE`-
The latest recommended time for the next sample, as determined by this
device. The actual time will probably be sooner than this.

`DTREQUIRED`-
The required approximate maximum time step, usually based on
truncation error estimation.

`CHARGE`-
The charge stored in this capacitor, in Coulombs.

`Q`-
The same as
`charge`.

`CAPACITANCE`-
The effective capacitance of this device. For a fixed capacitor, it
be its value. For a nonlinear capacitor, it is the effective
capacitance at this time, or ∂
*q*/ ∂*v*.

`DCDT`-
The time derivative of capacitance. For a linear capacitor it will be
zero.

`DC`-
The change in capacitance compared to the previous sample. Its
primary use is in debugging models and numerical problems. For a
linear capacitor it will be zero.

`DQDT`-
The time derivative of charge. Hopefully this is the same as current,
but it is calculated a different way and can be used as an accuracy
check.

`DQ`- The change in charge compared to the previous sample. Its primary use is in debugging models and numerical problems.